Vacuum exhaust-pipe



I (No Model.)

D. HARRIGAN.

VACUUM EXHAUST PIPE.

No. 263,514. Patented Aug. 29, 188-2.

. Invert/ i'an M I kgfim Nrrac STATES PATENT OFFICE.

DENNIS HARRIGAN, OF SOMERVILLE, MASSACHUSETTS.

VACUUM EXHAUST-Pl PE.

SPECIFICATION forming part of Letters Patent No. 263,514, dated August29, 1882.

Application filed July 13, 1882.

the same, reference being had to the annexed drawings, making a part ofthis specification, and to the letters and figures of reference markedthereon.

Figure 1 ot' the drawings is a perspective view of the complete devicewith the tips attached. Fig. 2 is a top View with the tips removed. Fig.3 is a top view of the tips. Fig.

4 is a section through Fig. 2 from A to B. Fig. 5 is a section throughFig. 3fro1nO to D. Fig. 6 isa bottom view of the complete exhaust, andFig. 7 is a bottom view of the tips.

The invention is intended not only to diminish what is called theback-pressure upon the piston, which naturally results from thecontraction of the nozzle of the exhaust-pipe, but to utilize suchback-pressure by creating a vacuum in front of the other advancingpiston. The arrangement of parts is such that this action alternatesfrom one piston to the other, according to which of the two exhaustpipesis in use for the escape of exhaust-steam.

The device hereinafter described is analogous to one for which LettersPatent No. 240,249, dated April 19, 1881 have been granted to me, butimproved and rendered more effective by a rearrangementand modificationofits parts. a

The exhaust-pipes-one for each cylinder-- are arranged near each other,as in the ordinary method, and united together in such way, by castingall but thetips in onepiece, so as to prevent any connection between thesteam-spaces e andf upon their opposite sides.

a b are the openings in the tips for the passage of the exhaust-steamafter leaving the main exhaust.

c d are the openings of the main exhaustpipes and represent the mainpipes.

g h are annular chambers surrounding the main exhaust-pipes, each havinga suitable opening into one of the steainspaces e f.

G is a plate forming part of the casting, ex-

(No model.)

tending around the outsides of the exhaustpipes, and sufficientlylargeto admit the inclosing of a space upon its surface outside theannular chambers to makethesteam spacesef.

Upon thejinside of the exhaust-pipe 0, near the point where theexhaust-steam enters, a port, k, of suitable dimensions, is cut throughits cylindrical wall for the passage of steam into the steam-space e,and a similar port, n, in the wall of the exhaust-pipe (1, allows thepassage of exhaust-steam into the steam-space f. At the opposite end ofthis steam-space f an opening connects with the annular chamber g, and asimilar opening from the steam-space e connects with the annular chamberh.

The tips are made in a separate casting, to be attached to the mainexhaust by screws at suitable points, so as to be removable at pleasure,and the openings a bin the tips aresomewhat reduced in size from thosein the main exhaust. The tips may bediscarded altogether by providingsuitable coverings t'orthestealnspaces ef, so as to prevent the escapeof steam except through theannularchambers; but the detachable tipsarein many respects preferable.

When in use the exhaust operates as follows: if the steam is passingfrom the cylinder upon that side through the exhaust-pipe c, thecontracting sides of that exhaust-pipe retard its escape, and a portionpasses through the port k and steam-space 0 into the annular chamber h,and thence outward through the tip I). This escaping steam, rushingthrough the tip bwhen the opposite side is exhausting, serves to createa vacuum in the main pipe (I, and thus assist in removing theobstruction of atmospheric pressure or dead steam from the path of theadvancing piston. Similar action takes place when the other cylinder isexhausting, but upon the opposite exhaust-pipe, and thus the actionalternates from one pipe to the other in perfect regularity, accordingto the strokes of the pistons on either side.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. Avacuum-exhaustconsistingof twopipes provided with steam-spaces, andannularchambers and suitable ports, and connecting-passages between saidspaces and chambers for creatingavacuum in the pipe not then exhaust- Intestimony that I claim the above I have hereunto subscribed my name inthe presence 10 of two witnesses.

ing, constructed and arranged substantially as I shown and described. I2. In combination withthe plateG,thepipes c (1, surrounded by theannular chambers g h, and the steam-spaces cf, provided with suitableports and connectirig-passages, with the tips (6 1), arranged andconstructed substantially as shown, and for the purpose set forth.

DENNIS HARRIGAN.

\Vitnesses:

3ERKLEY POWELL, EDGAR H. WooDMAN.

